Responsibilities
- Design, build, and maintain scalable backend systems supporting SumUp’s Bookings product.
- Collaborate with frontend and mobile engineers to deliver features and improve APIs across web, iOS, and Android.
- Participate in technical planning, code reviews, and design discussions.
- Optimize performance, ensure observability, and uphold reliability standards.
- Contribute to the technical roadmap for the Sell Online platform.
- Mentor peers and collaborate cross-functionally to deliver value to merchants.
Requirements
- 5+ years of professional backend engineering experience.
- Fluency in Kotlin or Java and deep experience with Spring Boot.
- Experience with PostgreSQL, Kafka, Docker, Kubernetes, and AWS.
- Understanding of RESTful APIs, distributed systems, and event-driven architectures such as CQRS and Event Sourcing.
- Experience with CI/CD pipelines, GitHub Actions, and observability tools such as Grafana or Honeycomb.
- Preferred: familiarity with gRPC, Protobuf, or backend and database performance optimization.
- Ability to work collaboratively, mentor peers, and focus on delivering value to merchants.
Benefits
- Hybrid work setup from SumUp’s Warsaw office in Hala Koszyki.
- Virtual Stock Option programme.
- Annual L&D budget of €2000 for conferences and further education.
- On-site gym and subsidized Multisport Card.
- Health insurance for the employee and family, plus life insurance.
- 26 days of paid leave, public holidays, and special leave days.
- One-month Break4me sabbatical after three years of service.
- Referral bonus programme.
- Diversity and inclusion initiatives and a collaborative workplace.
Tech Stack
Categories
About SumUp
SumUp is a leading global fintech company committed to levelling the playing field for small businesses. Founded in 2012, we’re the trusted partner of over 4 million merchants in 37 markets, providing simple and affordable tools that help them manage payments, finance, and customer relationships. Our vision is a world where everyone can build a thriving business. Guided by this, we champion small business ownership by creating accessible solutions that empower entrepreneurs to grow and succeed. Our diverse team of over 3,000 SumUppers — representing more than 90 nationalities across 20 offices worldwide — is at the heart of our success. Beyond business, we donate 1% of the net revenue generated by Solo devices to environmental causes and support educational and entrepreneurial initiatives around the world. Recognised as a Top Global Employer for inclusion by the Stonewall Workplace Equality Index in 2022 and 2023, and awarded Fintech Diversity Initiative of the Year at the Irish National Fintech Awards in 2025, SumUp continues to build an inclusive, supportive, and purpose-driven workplace where everyone belongs.